A semiconductor integrated circuit as a flat plate-like device under test is subjected to an electrical test as to whether it is produced as per specifications. The electrical test of this type is conducted by using an electrical connecting apparatus provided with a probe card having a plurality of contacts (i.e., probes) to be individually pressed against electrodes of the integrated circuit, a probe block, a probe unit and the like. The electrical test of this type is used for electrically connecting the electrodes of the device under test and testers.
There is one of such contacts used in the electrical connecting apparatus of this type which is shaped like a plate and a crank by using photolithography technology, deposition technology and the like (Patent Literature 1).
The contact comprises a first and a second arm portions extending in the right-left direction at vertical intervals, a first and a second coupling portions respectively coupling the first and second arm portions at their front end and rear end portions, a tip portion continuous to the lower side of the first coupling portion, and a mounting portion continuous to the upper side of the second coupling portion.
The first and second arm portions act as an arm region together with the first and second coupling portions. On the other hand, the tip portion acts as a tip region. The tip portion includes a pedestal portion integrally continuous to the lower edge portion on the front end side of the arm region, and a contact portion projecting downward from the lower end of the pedestal portion and having at the lower end a tip to be brought into contact with an electrode of the device under test at time of testing.
A conventional contact is cantilevered at its mounting portion on an adequate support base plate such as a wiring board or a probe board with solder or bond and assembled into an electrical connecting apparatus.
In a state that the electrical connecting apparatus is assembled into the tester, a plurality of contacts of the electrical connecting apparatus are illuminated from the tip side (the side of the device under test), and filmed by an area sensor like a CCD camera from the tip side. An output signal of the area sensor undergoes image processing to obtain the tip positions relative to the device under test (particularly, the electrodes) or the tester, and is used for positioning to determine the coordinate positions. By this positioning, the tip positions relative to the device under test on software or the tester are corrected.
Thereafter, an electrical test of the device under test is conducted. At the time of the electrical test, the tip of each contact is pressed against the electrode of the integrated circuit. Thereby, an overdrive force acts on the contact, and the contact is curved by elastic deformation at the first and second arm portions.
In the aforementioned conventional contact, in order to reduce a reflected light from the underside of its pedestal portion entering the area sensor, the lower side of the pedestal portion is formed as two inclined faces inclined to an imaginary axis extending horizontally and located in the right-left direction.
However, if the angles of both inclined faces to the imaginary axis are made small, the amount of light reflected from both inclined faces and entering the area sensor is increased, and it becomes difficult to accurately obtain the tip position relative to the device under test or the tester. As a result, it becomes impossible to accurately determine the tip position relative to the electrode of the device under test or the tester.
Unless the tip position can be accurately determined as mentioned above, accurate positioning of the tester or the device under test and the contact is not possible, and the tip of the contact cannot be pressed against the electrode of a predetermined device under test, so that it is not possible to conduct a correct electrical test.
If the angles of both inclined faces to the imaginary axis are increased (i.e., the angles formed between both inclined faces are made acute), the area of a joint portion of the pedestal portion and the contact portion is decreased, and the bond strength of the contact portion relative to the pedestal portion becomes insufficient, which might cause the contact portion to come off or break when an overdrive force acts on the contact acts.
Another contact is shaped like a pin with the lower end portion formed like a truncated conical shape (Patent Literature 2). As this contact cannot be produced by a photolithography technology, the production cost becomes expensive, and when an overdrive force acts on the contact, an elastic body such as a spring member to be elastically deformed like the arm region of the contact is required, so that not only the contact itself but also the structure of a support base plate supporting the contact becomes complicated.
Patent Literature 1: WO 2006/095441; Patent Literature 2: JP Patent Appln. DP No. 2002-5957